Spinning



Patented Nov. 26, 1940 UNITED STATES ".ATENT F SPINNING Robert Pierce Roberts and RobertMcVane Ding-' ley, Spondon, near Derby, England, assignors to Gelanese Corporation of America, a corporation of Delaware N Drawing.

rial No. 163,095.- 23, 1936 Claims.

canisation accelerators and a dispersing agent in amount suflicient to impart to the spinning solution a viscosity between about 135 and 165 on a scale in which the viscosity of a 70% solution of glycerine measured at 25 C. is 100. By a 70% aqueous solution of glycerine is meant a solution produced by diluting 70 volumes of glycerine with 30 volumes of water.

We have found .that the viscosity of the spin- I ning solution is of very great importance and that unless the viscosity lies within the limits specified above instability in spinning and/0r weak-, ness in the resulting thread is apt to result. One

of the most important factors effecting the viscosity of the spinning solution is the nature and amount of the dispersing agent used. We have found that the casein is particularly suitable as a dispersing agent for the purpose of the invention and is much superior for this purpose to dispersing agents such as gelatine, glue, viscose and soaps, for example the sodium, zinc or calcium salts of stearic, oleic, palmitic and similar Accelerators such as mercaptobenzthiazole alone I tend to coagulate the spinning solution. On the other hand accelerators such as diphenyl guanidine act too slowly to be used alone. Mixtures containing a member of each of these classes, however, ensure rapid vulcanisation without a danger of premature coagulation of the spinning solution. Thus the spinning solution may contain for example a proportion ranging from 0.25

higher fatty acids. The amount of casein used Application September 9, 1937, .Se-

In Great Britain September to 2%, e, g. 0.5 to 1%, of such a mixturege. g. a mixture of mercaptobenzthiazol'e and diphenyl guanidine in the ratio of about two to one, on the weight of the rubber. Other classes of accelerators, for example thexanthates such as sodium isopropyl xanthate,'dith'io acids, for instance sodium and zinc diethyl-thiocarbamates, and the thiuram sulphides, for instance tetrjaethylthiu ram-disulphide, are less suitable.

The spinning solution may contain in addition to the zinc oxide other white or coloured pigments. A very suitable white pigment for use is titanium oxide. When organic colouring agents are used care should be taken that these are stable towards sulphur.

antioxidant such for'example as the substance sold as Nonox S. 1

Spinning is preferablyefiected by extruding the solution into a coagulating bath comprising an aqueous solution of acetic acid, for example a solution containing 15-25% of acetic acid. Other dilute acids, however, can be used, forexample hydrochloric acid of similar pH value. After leaving the coagulating bath .the thread is preferably drawn first through a washing bath which may contaain for example 10-20% of am-' monium carbonate or other mildly alkaline substancein suitable concentration to neutralise the acidity resulting from the coagulating bath, and then through a bath containing a lubricant such as a textile soap adapted to prevent sticking of the threads during subsequent operations. A V 54.5% aqueous solution of a textile soap has been found suitable for this purpose. The useof such a lubricating bath has been found preferable to the use for the same purpose of solid substances such as French chalk or graphite. After leaving the lubricating bath the thread may be collected by suitable means and vulcanised in package form. We prefer to collect the thread on a collapsible swift and to remove the thread therefrom after drying and vuloanise it in hank form. Other methods of collection may, however, be used, for instance the thread may be deposited in loose coils in a, suitablecontainer an'd dried The spinning solution may also contain an.

and vulcanised before winding. The coils may be formed for example by reciprocating the container and the thread guide at right angles at lection may be used. Drying and vulcanising the thread continuously with its production is diifithe latex:

Per cent Titanium oxide 1 6 Zinc oxide 4 Sulphur I 3 Accelerator 0.5 Anti-ager 1 Casein 0.2

(The accelerator consists of amixture of mercaptobenzthiazole and diphenyl guanidine in the ratio of about 2:1).

These components are ground together in a small amount of water to a particle size of 1-2 a and added to the latex. If insuflicient Water has been used in the grinding to bring the viscosity of the final dispersion containing the latex to 165 further water is added until the viscosity is between 165 and 135 on the scale referred to above The resulting dispersion is spun into a 20% aqueous acetic acid bath at such a speed that the time of immersion is 9-10 seconds. The resulting threads-are carried through a washing bath consisting of a 15% aqueous solution of ammonium carbonate, then through an aqueous bath containing 10% of textile soap and are collected on collapsible swifts and dried thereon I,

that or" a 70% dispersion of rubber having a kinematic viscosity ranging from about 1.35 to about 1.65

times that of a 70% aqueous solution of glycerine measured at 25 C., said dispersion containing casein as a dispersing agent, and collecting the formed products.

2. Process for the production of rubber filaments, threads and like products which comprises spinning into an aqueous solution of acetic acid of about 20% strength, an aqueous dispersion of rubber having a kinematic viscosity ranging from about 1.35 to about 1.65 times aqueous solution of glycerine measured at 25 (3., said dispersion containing from 0.1 to 0.3% on the rubber content of the casein as a dispersing agent together with zinc oxide, sulphur and from 0.25 to 2% on the rubber content of a mixture of mercapto-benzthiazole and diphenyl guanidine in the ratio of about 2:1, the time of immersion in the bath being between 9 and 10 seconds, carrying the products through an aqueous solution of a mild alkali, then through an aqueous soap bath, collecting them, drying them and vulcanizing them.

3. A spinning solution for use in the production of rubber filaments, threads and like products, comprising an aqueous dispersion of rubber having a kinematic viscosity ranging from about 1.35 to about 1.65 times that of a 70% aqueous solution of glycerine measured at 25 C.

l. A spinning solution for use in the production of rubber filaments, threads and like products, cornprising an aqueous dispersion of rubber having a kinematic viscosity ranging from about 1.35 to about 1.65 times that of a 70% aqueous solution of glycerine measured at 25 C., said dispersion containing casein as a dispersing agent.

5. A spinning solution for use in the production of rubber filaments, threads and like products, comprising an aqueous dispersion of rubber having a ln nematic viscosity ranging from about 1.35 to about 1.65 times that of a 70% aqueous solution of glycerine measured at 25 C., said dispersion containing from 0.05 to 0.5% on the rubber content of casein as a dispersing agent together with zinc oxide, sulphur and a mixture of vulcanization accelerators, at least one being of the mercaptan class and at least another of the guanidine class.

ROBERT PIERCE ROBERTS. ROBERT MCVANE DINGLEY. 

